1. Field of the Invention
The present invention relates to a light source apparatus and a light-adjusting method for the light source apparatus, and more particularly to a light source apparatus including a plurality of illumination modes and a light-adjusting method for the light source apparatus.
2. Description of the Related Art
Conventionally, endoscope apparatuses have been widely used in medical fields and industrial fields. An endoscope apparatus is configured by including an endoscope, a video processor which is a main body apparatus to which the endoscope is connected, a light source apparatus which supplies illumination light to the endoscope, and a monitor on which an endoscopic image subjected to image processing in the video processor is displayed. The endoscopic image inside a subject, which is picked up with the endoscope is displayed on the monitor, and an operator is capable of performing examination and treatment inside of the subject.
In an endoscope apparatus, automatic light adjustment is performed so that an endoscopic image to be displayed on the monitor is displayed with appropriate brightness. The automatic light adjustment is performed by controlling a diaphragm device and a lamp in the light source apparatus on the basis of luminance information on the endoscopic image obtained by performing image processing on an image pickup signal outputted from the image pickup device in the endoscope.
Information related to the brightness of the endoscopic image obtained by picking up an image is supplied from the video processor to the light source apparatus for automatic light-adjustment. The light source apparatus adjusts an amount of the illumination light to be emitted toward the subject on the basis of the information such that the endoscopic image is displayed with appropriate brightness by stopping down a diaphragm of the diaphragm device when the endoscopic image is bright, and by opening up the diaphragm of the diaphragm device when the endoscopic image is dark.
On the other hand, endoscope apparatuses include an endoscope apparatus having a plurality of observation modes. Observation modes include a normal light observation mode in which a subject is irradiated with white light in a visible light band and observed, a special light observation mode in which a subject is irradiated with light in a predetermined band and observed, and other modes. A light source apparatus includes illumination modes corresponding to the observation modes. The endoscope apparatus having a plurality of observation modes enables not only an observation of a subject under normal light but also an observation of the subject under special light by switching the observation modes.
In addition, as disclosed in Japanese Patent Application Laid-Open Publication No. 2009-148487, a light source apparatus is proposed in which a control signal for light amount control is fixed to a predetermined value during switching of the observation modes, in order to improve a response degradation of the light amount control caused by a variation of the illumination light amount which occurs at the time of switching the observation modes.